Relying party

A relying party is an entity that needs to control access to a resource and, to do so, needs to authenticate other entities that are trying to access that resource. On the web, a relying party is usually a website that allows users to sign in and needs to authenticate users (for example by checking a password) before deciding whether to grant them access.

The website relies on the validity of the credentials the browser presents when it grants access to its resources.